1. Field of the Invention
The present invention relates to a mobile terminal on which a noncontact IC card function is provided and a control program thereof.
2. Description of the Related Art
A lock function that disables the mobile terminal from using the noncontact IC card function is provided to prevent a third party from using the mobile terminal without the owner's authorization at the time of theft or loss of the mobile terminal on which the noncontact IC function is provided.
By the way, the noncontact IC function can be the object of a function that allows the mobile terminal to be used at a minimum level, the same as in an internal clock or the like, even when the residual amount of a battery is low in the mobile terminal.
However, the mobile terminal has a problem in that a function that locks the noncontact IC card function accompanied with a screen display can't be released if the residual amount of the battery is low in a lock state, because the function can't be an object at a time when the residual amount of the battery is low.
Particularly, if a commuter passes through one station ticket gate by using a transportation ticket service that is one of the services utilizing the noncontact IC card function and the residual amount of the battery is low before the commuter goes out of another station ticket gate, situations such that the commuter can't release the lock thereof and pass through the station ticket gate take place.
Otherwise, as in an electronic ticket, when a person is scheduled to use the noncontact IC card function within a predetermined term, a problem such that a scheduled service can't be received is liable to occur if the residual amount of the battery is low and the lock thereof can't be released. Then, the lock must be released in any manner.
Here, the lock release is to release the lock state of the noncontact IC card function to allow the noncontact IC card function to be used.
In the noncontact IC card function, as a method to release the lock, for example, a technology that a personal identification number (PIN) is preset by service and the noncontact IC card function is allowed to be used by authenticating the PIN to prevent a third party from wrongfully using the noncontact IC card function at the time of theft or loss is disclosed (for example, refer to Japanese Laid-Open (Kokai) Patent Publication No. 2003-16398).
In addition, Japanese Laid-Open (Kokai) Patent Publication No. 2006-13603 is disclosed as another related prior art.
This technology identifies a problem such that a commuter can't enter or go out of a station ticket gate if the residual amount of a battery is low and a power supply is turned off when the commuter utilizes the noncontact IC card function for entry/exit at a station ticket gate or the like. As a countermeasure to solve the problem, it is designed to prevent the lowering of a battery remaining amount by allowing the user to select either an authentication function or communication function of the noncontact IC card function at a time when the battery remaining amount becomes less than the threshold.
However, the related prior art disclosed in Japanese Laid-Open Publication No. 2003-16398 never touches on the problem that a noncontact IC card can't be used accompanied with the lowering of a battery remaining amount. Therefore, the related art has a problem that the lock can't be released if the residual amount of a battery is low in the lock state.
Meanwhile, in the related prior art disclosed in the Japanese Laid-Open Publication No. 2006-13603, it is said that the noncontact IC card may be used by a point at a time when any one of the functions (i.e., either the authentication function or communication function of the above-described noncontact IC card) can be preferentially used or by a time when any one of them can be preferentially used. However, the related art also has a problem such that the lock can't be released if the residual amount of a battery is low with the card locked as it stands and the power supply is turned off.